At present, most dental procedures are done large, overhead projection light source which focuses the light beam onto the patient's mouth using concave mirrors. Within the mouth, detailed examination is done using a small, circular dental mirror affixed at the end of a handle, This mirror reflects the overhead light beam to the area of the mouth being studied, and also reflects the illuminated image back to the eye(s) of the dental technician or dentist. In order to concentrate the light further, or to get an enlarged image, one can use a mirror with a concave reflecting surface. Furthermore, an overhead light requires frequent adjustment which increases the danger of contamination.
After use with a patient, the hand-held dental mirror is autoclaved to sterilize it, to prevent infection and contamination of the next patient for which it is used. Although dental personnel now typically wear gloves, masks, and even goggles to avoid infectious diseases, this mainly protects the dental person, and only indirectly protects each patient. If an overhead lamp is used for illumination, the redirection or refocusing of this lamp requires hand contact by the dental person, and this can lead to cross-contamination of patients. In order to minimize this cross-contamination, a variety of handle covers have been devised and commercialized.